Rammer

ABSTRACT

Rammer for those artillery pieces which are charged with a shell and propellant separately, intended to move the shell, upon charging the piece, from a charge position in the immediate vicinity of the charge opening of the piece to the rammed position of the shell inside the barrel ahead of the charge space intended for the propellant powder charge. The rammer, which preferably is hydraulically operated, is divided into two piston cylinder systems consisting of a primary rammer and a secondary rammer connected by means of a transverse arm and designed with parallel but counter-directed projection directions. Immediately before the rammer is activated, the secondary rammer is situated along the longitudinal axis of the barrel and with its own piston rod completely retracted immediately behind the shell situated in the charge piston, while the primary rammer is at the same time completely projected. Upon ramming, the primary rammer is drawn in and the secondary rammer is pushed out. The invention also includes a swivel function which makes it possible to move the rammer aside from its active position behind the piece to a rest position at the side of the piece.

FIELD OF THE INVENTION

The present invention relates to a rammer for artillery pieces which areseparately charged with a shell and propellant charge.

BACKGROUND OF THE INVENTION

The purpose of the rammer is to drive the shell, upon charging of thepiece, into its rammed position in the barrel, with at least one of thebourrelets of the shell in such close contact with the lands of thebarrel rifling that the shell remains in the rammed position even at themaximum elevation of the piece. This is necessary in order to permitintroduction of the propellant powder charge into its position in thecharge space situated behind the rammed shell. The normal chargingprocedure begins by being the shell into the immediate vicinity of theopen rear section of the artillery piece, for example on an in-swingingcharge cradle, after which a rammer of one type or another drives theshell into its rammed position. Since, as has already been mentioned,there must be space behind the shell for the propellant powder chargeitself, the distance by which the rammer must move the shell into thebarrel is relatively long.

Moreover, the shell must be driven in with a certain force in order forit to remain there even when the piece is at its maximum elevation. Inthe case of purely axially displaceable rammers, this results incomparatively long constructions. On the other hand the known morecompact rammer constructions have had to rely on a relatively longso-called free flight for the shell, which means that it makes contactwith the rammer only during a relatively short part of the rammingdistance from the charge position to the rammed position, but that theshell during this relatively short part of the ramming distance is givena sufficient speed so that, after the contact with the rammer hasceased, it can continue, by means of a combination of the acquired speedand the intrinsic gravity, into its rammed position with sufficientforce to give the desired engagement in the barrel grooving.

An example of such a rammer with a long free flight for the shell isdescribed in German Offenlegungsschrift 3,607,006. However, a long freeflight constitutes a factor of unreliability, since in this case thereis poor control of how good the ramming actually is in each particularcase.

The purpose of the present invention is primarily to provide a rammerwith a short free flight and a very compact construction. In addition,the construction of the rammer according to the invention includes asmall number of simple and strong components.

Furthermore, the construction according to the invention has made itpossible, in the case of hydraulic operation of the rammer, to limit thenumber of hydraulic connections to a minimum, and at the same time, dueto the special design of the rammer, these connections can be made inthe form of fixed connections on the breech casing of the piece, whichtherefore do not participate in the recoil of the piece, which is alsovery advantageous as regards both operational reliability and servicingrequirements.

These advantageous characteristics of the rammer according to thepresent invention come fully into play in connection with modernizingolder types of armored-turret-protected pieces which were originallycharge manually, of which there are a very large number dating from thesixties and the beginning of the seventies and whose value would beincreased to a very great extent if they could be provided with whollyautomatic or semi-automatic charging systems instead of their previousmanually charging systems. Since these pieces are already mounted inarmored turrets with limited internal space, the requirement for compactcharging systems is very significant. In addition, it must be possibleto mount the charging system with place without significant interferencein the artillery piece system as such or its possible auxiliary systems.

The rammer according to the present invention is thus primarily intendedfor those artillery pieces which are separately charged with the shelland propellant powder charges (powder bags). Upon charging of the piece,the rammer will move the shells from a charging position wholly orpartly outside the rear charge opening of the piece to the rammedposition of the shell ahead of the charge space intended for thepropellant powder in the rear section of the barrel. As has already beenmentioned, this displacement is at present relatively long and willprobably be longer in future, since in recent times shells continue tobecome longer and narrower in line with the increase in the firingranges of artillery pieces. Regarding the requirement for driving theshells at a certain force into the rammed position so that they remainthere even when the piece is at its maximum elevation, it should bementioned that the armored-turret-protected pieces are often of thehowitzer type and have a maximum elevation of 75°-80° relative to theground level.

The shells are brought to the charging position immediately outside therear charge opening of the barrel either on an in-swinging chargecradle, usually provided with special securing members for the shells,or else the shells are placed manually in the charging position. With anappropriate design of the suspension of the charge cradle, the lattercan be made to swing the shell at least partly into the charge openingof the piece. This of course facilitates the ramming.

The rammer according to the present invention, like most other rammers,is designed to grip behind the shell and push it forwards from thecharge cradle to the rammed position of the shell inside the barrel. Ashas already been pointed out, the shortest possible free flight for theshell is desired here. The inventors have now succeeded in achieving amaximum ram travel for the rammer according to the invention within aminimum space requirement by dividing the rammer into two pistoncylinder systems which are connected to each other by means of atransverse arm and are axially displaceable parallel to each other andto the barrel from and to their respective zero positions. These pistoncylinder systems define a primary and secondary rammer whose combinedram travel corresponds to the distance which the rammer is to move theshell, and the cylinder of the primary rammer is arrangednon-displaceable relative to the breech casing of the piece, while thetransverse arm is connected to the displaceable piston rod of theprimary rammer, and the cylinder of the secondary rammer is securelyconnected to the other end of the transverse arm. Moreover, theprojection direction of the primary rammer piston is directed rearwardsalong the barrel of the piece and identical to the retraction directionof the secondary rammer piston. This means that the projection directionof the secondary rammer piston is directed forwards in the barreldirection. The two cooperating rammers are moreover mounted on the piecein such a way that, when the primary rammer is completely projected andthe secondary rammer completely retracted, the front part of thesecondary rammer, that is to say the front part of its piston rod, isimmediately behind a shell situated on the charge cradle or the like.With this design of the rammer, the ramming is effected by means of acombination of projection of the secondary rammer and retraction of theprimary rammer.

According to this invention, the rammer is additionally designed in sucha way that, as long as it does not extend into the charge space of thebarrel, it can be swivelled aside about the attachment of the transversearm on the primary rammer, so that the secondary rammer is completelyturned away parallel to the side of the barrel axis, that is to say awayfrom the rear charge opening of the barrel.

By means of retraction of the primary rammer piston, the whole rammercan thus be transferred to a rest position alongside the barrel.

The possibility of moving the secondary rammer to the side is also usedwith advantage after ramming in order to facilitate the swinging-in ofthe charge cradle with a new shell. This possibility also means that,upon firing, no separate space for the rammer is required behind thepiece upon recoil of the latter.

The rammer according to the invention has been defined more closely inthe subsequent patent claims and will now be described in somewhatgreater detail together with the exemplary embodiment shown in theattached drawings, wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a section through an armored turret with a mountedartillery piece of high elevation and provided with the rammer accordingto the present invention;

FIG. 2 shows a section through the rear part of a barrel provided withthe rammer according to the present invention in its foremost position(rammed position);

FIG. 3 shows the same piece as in FIG. 2 as seen from the rear, but atthe time immediately before the charge cradle has been swung intoposition behind the barrel;

FIG. 4 shows a perspective more detailed view of the rear part of anartillery piece provided with the rammer according to the invention,where the ramming has just begun;

FIG. 5 shows the principle of the rammer; and

FIGS. 6a-e show the principles of the rammer functions (for the sake ofclarity the swivel function has been omitted in these figures).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

The armoured turret 1 shown in FIG. 1, which can be part of, forexample, a track-laying vehicle such as a CATERPILLAR®-tracked armoredhowitzer, comprises a howitzer 2 whose rear section ends at 3 but, uponrecoil, drops down to the position as indicated 3a. The breech screw,open in the drawing, is indicated by 4. A rammer 5, a charge cradle 6and finally a shell 7, which is about to be rammed, can also be seen inFIG. 1. For further details regarding the design of the charge cradleand the rammer, reference will be made to the other figures. FIG. 1 alsoshows a charger 8 whose task is to ensure that the correct shell fromthe shell stock 9 is placed on the charge cradle 6. In the case shown,it is assumed that the charger 8 positions the shells manually on thecharge cradle 6, which is then swung in for ramming of the shell.However, the transfer of the shells to the charge cradle can also beautomated, but is not relevant the present invention and for this reasonis not discussed here.

As far as possible, corresponding components have been given the samereference designations in the various figures.

FIGS. 2 to 4 show more details than in FIG. 1, but in FIG. 4 also therear section of the piece is referred to by 3, and the breech screw 4 issecured on the latter.

In front of the open breech screw 4 lies the charge opening 10 of thepiece, and in front of this the charge space 11 intended for thepropellant powder charge (see FIG. 2). The charge cradle 6 (see FIG. 4)is suspended on swinging arms 12 and 13 and is maneuvered by means ofthe hydraulic cylinder 14. For holding the shell 7 on the charge cradleright up to ramming, there is also provided a hydraulically operatedholding device 15.

The rammer 5 includes of a primary rammer 16 consisting of a hydrauliccylinder 17, in this case fixed on the topside of the breech casing, anda piston rod 18 which can project in the rearwards direction of thepiece parallel to the extent of the barrel. Moreover, parallel to theprimary rammer and maneuvered by the latter, is an axially displaceableguide beam 19. This in turn contains an oil reserve for the hydraulicsystem. The design of the latter will be discussed in greater detail inconjunction with FIGS. 5 and 6a-e. At the common end section 20 of theguide beam 19 and the primary rammer piston, a transverse arm 21 issecured in such a way as to be able to swivel around, and secured at theother end of the transverse arm is the cylinder 23 of a secondary rammer22. The piston rod of the latter has the reference 24. The piston rod ofthe secondary rammer projects into the barrel 2.

In order for the rammer to be moved aside from the charge opening 10,there is a swivel function consisting of a hydraulic cylinder 25 whichacts on a spline shaft 26 on which a gearwheel 27 is connected innon-rotational manner. When the gearwheel 27 is turned, this in turnacts on a second gearwheel 28 which is connected securely to thetransverse arm 21, which is then swivelled around. As shown, forexample, FIG. 3, the secondary rammer can in this way be moved betweenthe two positions I and II shown in the figure, where position I is arest position and position II is a ramming position.

As further seen from FIG. 2, the secondary rammer, upon maximumprotection and when combined with a completely retracted primary rammer,reaches the end position S. The rammed position A of the shell is alsoindicated in the figure with broken lines. Between positions S and Athere is a relatively short free flight distance which the shell crossesas a result of the speed which has been imparted to it before it reachesthe end point S for the advance of the rammer.

The ramming is thus effected in the following manner:

The shell 7 is placed by the charger 8 in the charge cradle 6. Assumingthat the charge opening 10 is now open, due to the fact that the breechscrew 4 has been moved aside, then the charge cradle 6 can be swung intothe mouth of the charge opening 10 with the aid of the piston 14. Thenext step is to activate the rammer 5 situated in the rest position I,in which the primary rammer 16 has first been moved to its fullyprojected rear position, and then the transverse arm 21 with thesecondary rammer 22 is swung to position II by means of the piston 25,the shaft 26 and the gearwheels 27 and 28. When the secondary rammer 22has reached position II, the outer end of this rammer is situatedimmediately behind the rear end of the shell 7. The ramming is activatedin this position, and at the same time the retention member 15 isreleased. Upon ramming, the primary rammer will be drawn into the fullyretracted position and the secondary rammer will be pushed outcompletely. These two actions are either effected consecutively or, morepreferably, to some extent simultaneously, since the velocities are thenadded. The best result is achieved if the primary rammer, whichexpediently has the longest ram travel, is initiated first and is drivenalone a first distance at relatively low velocity, and only then is thesecondary rammer initiated and driven parallel to the primary rammer.The velocities of the rammers are thus added together during the finalpart of the ramming of the shell, as a result of which the necessaryramming velocity is obtained. When the outer end of the secondary rammer22 has reached position S, the shell 7 will have acquired a velocitysufficient for the shell to cross the distance A-S under its own forceand to have a sufficient kinetic energy, when it reaches A, to securethe shell against the lands of the grooves in the rammed position aheadof A.

Regarding the charging operation, it only remains now, after the chargecradle has been swung aside, to introduce the propellant powder into thecharge space 11 behind the shell and to close the breech screw.

The principles of the hydraulic system will now be described in greaterdetail in combination with FIGS. 5 and 6a-e.

These figures correspond except for the different scale and for the factthat the swivel function has been omitted in FIGS. 6a-e for the sake ofclarity. The main parts have the same references as in the otherfigures, although we have been sparing in our use of these in FIGS.6a-e. The swivel function, as it appears in FIGS. 5, is somewhatsimplified compared to the other figures.

As can be seen from the figures, the cylinder 17 of the primary rammer16 constitutes an integral unit with the guide beam 19 and its built-inoil reserve. Apart from the swivel cylinder 25, which has its ownconnections for the hydraulic oil, there are four connections 29-32 forcontrolling the various functions of the rammer. All these connectionsare located on those parts of the primary rammer and guide beam whichare stationary relative to the breech casing of the piece. The guidebeam 19 in FIG. 4 corresponds in functional terms in the outlinesketches in FIGS. 5 and 6a-e to the piston rod 19', which differsslightly in appearance but not in terms of function from the otherfigures. The piston rod 19' is displaceably mounted in the cylinder 33,which constitutes the oil reserve referred to earlier in the text. Thecylinder 33 is built integral with the cylinder 16 of the primaryrammer. Since the part 16-33 is fixed, the connections 29-32 can also bemade fixed, which is extremely advantageous with regard to design,servicing and operating.

The displaceable piston rod 18 of the primary rammer correspondsentirely to the other figures.

The swivel function is shown here diagrammatically at 34, while thetransverse arm 21 and the secondary rammer 22 corresponds entirely interms of concept with the other figures.

Of the hydraulic oil connections, 29 leads to the return side 35 of theprimary rammer and 30 leads to its projection side 36, while 31 opensinto one side 37 of the reserve oil supply and reaches from there, via aline 38 through the piston rod 19' and the transverse arm 21, to theprojection side 39 of the secondary rammer 22, while the connection 32opens into the other side 40 of the piston 41 on the piston rod 19'. Thepiston 41 divides this part of the oil supply from its other side 37.From the space 40, the connection 32 leads to the return side 42 of thesecondary rammer via a second channel 43 which likewise passes throughthe transverse arm 21 and opens out at the return side 42 of thesecondary rammer.

In FIGS. 6a-e, 6a indicates the zero position at position I, and 6bindicates the projection of the primary rammer, after which swivellingto ramming position II takes place, while FIG. 6c shows an initiatedramming, FIG. 6d shows the returned rammer just before swivelling backto position I, and FIG. 6e shows the retraction of the primary rammer.

Starting with FIG. 6a, which shows the zero position, the function foractivating the rammer (see FIG. 6b) now involves applying a pressure tothe connection 30, at the same time as a draining is effected via theconnection 29. At the same time, a draining is effected at 31 and afilling at 32. At the same time, hydraulic oil is forced via the channel43 to the return side of the secondary rammer 22.

When the primary rammer has reached its outermost position, the rammeris swivelled back from position I to position II. This thus takes placebetween FIGS. 6b and 6c.

For activation of the rammer function, a pressure is applied at 29,which draws in the primary rammer, which thus requires drainage via 30.If a pressure is applied at the same time at 31, the secondary rammer isactivated via the channel 38, provided that a draining is effected via32. This is shown principally in FIG. 6c.

After the ramming, the secondary rammer is to be drawn in and theprimary rammer pushed out in order for the whole rammer to be moved awayto its rest position. The two first-mentioned movements are initiatedmore or less simultaneously by applying a pressure at 30 and 32 anddraining via 29 and 31. The hydraulic fluid pressure from 32 reaches thereturn side of the secondary rammer via the channel 43. FIG. 6d showsthe end position of these movement.

Between FIGS. 6d and 6e the rammer is swung aside to the rest position(I) with the secondary rammer at the side of the barrel, after which theprimary rammer is again drawn in, which is shown in FIG. 6e, while thesecondary rammer is held back in its zero position. Here, pressure isapplied at 29, drainage is effected via 30 and 32 and filling via 31.

The invention is not limited to the exemplary embodiment discussedabove, but instead can be modified within the inventive concept asdefined in the patent claims.

We claim:
 1. A rammer for use with an artillery piece having a rifledbarrel with a breech casing which is separately charged with a shell anda propellant, said rammer adapted to charge said shell into said barrelfrom a charge cradle which is positioned adjacent a charge opening insaid barrel and to drive said shell into a rammed position in a chargespace provided in said barrel for said propellant and in contact withrifling in said barrel;said rammer comprising primary and secondarypiston-cylinder systems having pistons which are axially disposedparallel to each other and to said barrel, and a transverse arm memberhaving first and second end portions connecting said piston-cylindersystems together so that their combined travel corresponds to thedistance by which said rammer will move said shell, the cylinder of saidprimary piston-cylinder system being fixed relative to said breechcasing and the piston thereof being connected to said first end portionof said transverse arm member, and directed rearwardly along the rearsection of the barrel, and the cylinder of said secondarypiston-cylinder system being securely connected to said second endportion of said transverse arm member, the piston thereof having itsdirection of rammer movement oriented toward said charge space so thatwhen the piston of the primary piston-cylinder is in a fully projectedposition and the piston of the secondary piston-cylinder is in acompletely retracted position, said piston of said secondary pistoncylinder is adapted to be positioned inwardly behind a shell lying onsaid charge cradle.
 2. A rammer according to claim 1 wherein saidtransverse arm member and the cylinder of the secondary piston-cylindersystem secured thereto is adapted for swiveling from a first restposition where said cylinder of said secondary system lies beside thebarrel to a second activation position where the axis of the secondarysystem coincides with the axis of the barrel.
 3. A rammer according toclaim 1 including a hydraulic control system for maneuvering thecomponents of the piston-cylinder system.
 4. A rammer according to claim3 including a hydraulic cylinder for swiveling said transverse arm.
 5. Arammer according to claim 1 wherein the piston of said primarypiston-cylinder system has a longer travel path than the piston of thesecondary piston-cylinder system.
 6. A rammer according to claim 2including a guide beam on which said transverse arm is rotatablymounted, and means interconnecting said guide beam with said primarypiston-cylinder system for moving said guide beam.
 7. A rammer accordingto claim 6 wherein said rammer includes a hydraulic control system andmeans are provided in said guide beam for containing an oil supply forsaid hydraulic system.